Lunytune wrote:Not sure if everybody caught it but I did. However, in afterthoughts, I wonder why people say the Honda won't run without the airbox. I've run my Banshee without an airbox, and that's when it has its most power. Seems to me that with airbox properly installed, cover and all, you've added SEVERAL inches to the air column and RPM would be cut drastically. This causes me to be in question of Mouse's "formula". Or is it like a synewave and finds another peak? That's the way things work in ballistics.Wheelman-111 wrote:The point I was driving at wasn't clear in my first post, so I'll try again.
The point was supposed to be that Honda's intake tract is so long (is it around 7" long from reed block to carb bellmouth?)that if we follow the "formula" submitted by Mouse we arrive at a peak output RPM somewhere just north of 6K. Anything added to the air column - like the stock airbox or a velocity stack - increases the effective length and thereby focuses peak power at an even lower RPM.
The trouble with the scooter motors is that they are so low on power to start with (you can look at that as it doesn'r suck very well
) that without the air box on the front of the carb, they are so gutless as to be unable to cause the fuel system in the carb to transition to the high speed circuit, IE the main jet, hence they stumble and die when the throttle is opened. Almost all of the small 2 stroke outboards built in the late 80 and the 90s were this way until the EPA killed small 2 stroke marine engines all together (The EPA are attempting the same thing with all 2 stroke engines). The intake system needs to be close to what it was designed to function at or the carburetor just does not function properly. All of this is under a load of course. Reving an engine unloaded takes so little throttle opening and fuel that if it doesn't run that way your high speed fuel circuit has to be plugged. As long as you retune the intake runner to close to the stock length, then you would be good to go. But you must remember that the whole intake system is just that, a system design to function together and changing one item without compensating for the that change with other changes. The use of booster venturis in the carb can help relieve this issue.